mc9s12c32mpb16 Freescale Semiconductor, Inc, mc9s12c32mpb16 Datasheet - Page 657

• Manufacturer Part Number: mc9s12c32mpb16
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

The loop bandwidth f
typical values are 50. ζ = 0.9 ensures a good transient response.
And finally the frequency relationship is defined as
With the above values the resistance can be calculated. The example is shown for a loop bandwidth
f
The capacitance C
The capacitance C
A.4.3.2
The basic functionality of the PLL is shown in
deviation from the reference clock f
The adjustment is done continuously with no abrupt changes in the clock output frequency. Noise, voltage,
temperature and other factors cause slight variations in the control loop resulting in a clock jitter. This jitter
affects the real minimum and maximum clock periods as illustrated in
Freescale Semiconductor
C
=10kHz:
R
Jitter Information
=
C
2 π n f
---------------------------- -
s
p
s
can now be calculated as:
should be chosen in the range of:
⋅ ⋅
C
f
=
C
K
should be chosen to fulfill the Gardner’s stability criteria by at least a factor of 10,
n
Φ
--------------------- -
π f
<
2 ζ
⋅
C
=
⋅
------------------------------------------
π
⋅
C
s
C
⋅
f
------------ -
⎛
⎝
VCO
⁄
f
⋅
2 ζ f
2
ζ
ref
20
R
= 2*π*50*10kHz/(316.7Hz/Ω)=9.9kΩ=~10kΩ
⋅ ⋅
+
ref
MC9S12C-Family / MC9S12GC-Family
≈
≤
is measured and input voltage to the VCO is adjusted accordingly.
=
0.516
-------------- - ζ
f
C
1
C
ref
p
+
2
⋅
≤
R
ζ
⋅
2
(
C
;
Figure
synr
⎞
⎠
(
s
Rev 01.23
⋅
⁄
---- -
10
=
10
1
0.9
+
A-3. With each transition of the clock f
→
1
)
f
)
f
C
C
C
p
= 5.19nF =~ 4.7nF
<
< 25kHz
= 470pF
= 50
------------ - ζ
4 10
f
ref
⋅
Figure
;
(
Appendix A Electrical Characteristics
=
A-4.
0.9
)
cmp
, the
657